Assessment of the Feasibility of Using Local Fill Materials in the Southern Key Economic Region for Roadbed Construction in Low-Lying Riverside Areas

Abstract

The administrative boundary merger  of Southern provinces and the large-scale infrastructure development orientation have created an urgent demand for fill materials, particularly for road subgrades in floodplain areas of the southern key economic region. In the context of increasingly scarce traditional materials, limestone crushed stone mix of 0÷4,0 cm, widely distributed in the mountainous areas bordering Cambodia, emerges as a potential alternative due to its good mechanical properties and easy local availability. This study evaluates the feasibility of using this material combined with 10÷20% fly ash from the Duyen Hai 1 thermal power plant to improve strength, water resistance, and reduce settlement. The results indicate that the material meets technical requirements, reduces costs, utilizes industrial waste, and aligns with the principles of the circular economy. Furthermore, the study emphasizes the importance of sustainable extraction management and the establishment of local technical standards, contributing to the development of green and sustainable infrastructure in the southern key economic region.